1. Field of the Invention
The invention is generally related to co-polymer tiles and more specifically to a tile having a simulated wood-grain appearance and to a method of manufacture of same.
2. Description of the Related Art
Co-polymer tiles are commonly used in commercial, industrial and residential applications. Co-polymer tiles are widely used as floor tiles as they provide a durable floor surface that is easily cleaned. Co-polymer tiles are readily transportable and installed.
Co-polymer tiles are typically formulated using a co-polymer resin, a plasticizer, a stabilizer and a limestone (calcium carbonate) filler. Exemplary descriptions of formulations used to manufacture co-polymer tiles are found in U.S. Pat. No. 3,991,006 issued to Chandler
Referring to FIG. 5 (Prior Art), the current practice of manufacture of co-polymer tiles includes the following steps:
Mixing Step: A mixing step 301 including mixing a minor proportion of co-polymer resin and a major proportion of a mineral filler together with a plasticer and a stabilizer. Appropriate resins, filler, plasticizer and stabilizer are commonly known and commercially available in the industry. The mixture is mixed under pressure to obtain uniform color and texture in an appropriate mixer, such as a Banbury mixer manufactured by Farrel Corporation. As is known to those skilled in the art, the Banbury mixer includes rotors and a pressure ram that may be engaged to increase pressure on the mixture during the mixing process. Mixing in the Banbury mixer comprises a batch operation with the mixture released through a gate provided in the mixer upon completion of the mixing process. A coloring agent is added in the mixing stage to obtain a desired color characteristic of the product. Upon mixing, the mixture has a substantially uniform mix and color and is at a temperature of approximately 170° C. (338° F.). Mixing time of a typical batch of co-polymer tile ingredients in a Banbuiy mixer is in a range of one to two minutes.
Compression Step: In a compression step 302, the mixture is then processed between opposed rollers of a roller mill to remove air from the mixture. The exterior surface of each of the rollers is essentially smooth. As the mixture is pulled between the rollers, the mixture tends to adhere to each of the rollers.
Scratching Step: In a scratching step 303, the mixture is then processed between one of the rollers of a roller mill and a scratching roller in a step commonly referred to as scratching. In such process, the exterior surface of a third scratching roller is provided with a plurality of cylindrical pins. The pins of the scratching roller extending outwardly from the exterior surface. The axis of the scratching roller is aligned with one of the rollers of the roller mill. As mixture is rotated between the mill roller and the scratching roller, the plurality of pins of the scratching roller break the mixture into relatively small clumps. The separated clumps fall onto a receiving conveyor.
Sheeting Step: In a sheeting step 304, the clumps of mixture are then processed between rollers of a roller mill. In this step the rollers each have continuous smooth exterior surfaces that form the mixture into an elongated, continuous planar sheet having a relatively smooth top and bottom surfaces and uniform thickness.
Calendering Step: In a calendaring step 305, the sheet of mixture is heated and passed through a plurality of calendaring rollers to reduce the thickness of the sheet to a desired thickness.
Cooling Step: In a cooling step 306, the sheet is then cooled, typically by a water spray.
Surface Treatment Step: In a surface treatment step 307, a surface treatment such as wax, is applied to the top surface of the sheet and the top surface is buffed to provide a suitable sheen.
Stamping Step: In a stamping step 308, the sheet is then cut into a plurality of tiles of desired length and width dimensions, typically by a stamp.
Cuttings remaining after the stamping step 308 may be introduced into the mixing step 301 as the finished product becomes pliable and capable of uniformly mixing with the mixture at the temperature and pressure of the mixing step 301.
Co-polymer tiles are currently manufactured with a variety of patterns. As presently practiced, patterns are introduced into the tiles by adding mottle to the mixture intermediate the scratching step 303 and the sheeting step 304. Mottle comprises chips of co-polymer mixture of a different color from the mixture base color. The mottle chips are engrained in the mixture by pressure and the temperature of the mixture at the sheeting step 304. Such patterns may comprise elongated colored segments of limited length.
It is desirable to create a co-polymer tile having a pattern simulating wood grain as wood floors and floors providing a simulation of wood appearance are desirable. Prior art attempts to create such a wood grain pattern have not been successful.